The present invention relates to methods of modulating the activity of NF-xcexaB and to methods of inhibiting the IxcexaB complex (IKK) using cyanoguanidine derivatives.
Neoplastic diseases are characterised by autonomous growth of cells. Neoplastic diseases may be benign, i.e. the growth is contained and does not spread to other organs or parts of the body. Neoplastic diseases may also be malignant where the growth spreads to other organs or parts of the body by infiltration or metastases. Malignant neoplastic diseases are also known as cancers.
Patients with neoplastic diseases are treated by surgery, ionising radiation, medication, or a combination thereof. Several types of medicaments or drugs for the treatment of neoplastic diseases are known, and one way of classifying these medicaments is suggested in Abeloff et al (Eds.), Clinical Oncology, Churchill Livingston Inc., New York, 1995, Medicaments for treatment of neoplastic diseases may conveniently by classified as chemotherapeutic agents, hormonal agents or biological response modifiers.
Chemotherapeutic agents may further be classified according to the mechanism whereby they effect their response as S-triazine derivatives such as altretamine; as enzymes such as asparaginase; as antibiotic agents such as bleomycin, dactinomycin, daunorubicin, doxorubicin, idarubicin, mitomycin and plicamycin; as alkylating agents such as busulfan, carboplatin, carmustine, chlorambucil, cisplatin, cyclophosphamid, dacarbazine, ifosfamide, lomustine, mechlorethamine, melphalan, procarbazine and thiotepa; as antimetabolites such as cladribine, cytarabine, floxuridine, fludarabine, fluoruracil, hydroxyurea, mercaptopurine, methotrexate, pentostatin and thioguanine, and as antimitotic agents such as etoposide, paclitaxel, teniposide, vinblastine and vincristine.
Hormonal agents may be further classified according to the mechanism whereby they effect their response, e.g. as aromatase inhibitors such as aminoglutethimide; as antiestrogens such as tamoxifen, formestan and letrozol; and as antiandrogen such as flutamide.
Biological response modifiers may be further classified according to the mechanism whereby they effect their response as e.g. lymphokines such as aldesleukin; as interferon such as interferon-xcex1 and as growth factors such as erythropoietin, filgrastim and sagramostim.
A number of medicaments do not fall naturally within this classification. Examples of such medicaments are anti-proliferative and/or cell differentiating agents such as all-trans retenoic acid or vitamin D analogues such as seocalcitol.
Other types of medicaments based on e.g monoclonal antibodies, tumour necrosis factor, gene therapy and angiogenisis inhibitors have been suggested for treatment of neoplastic diseases, but they are still in the exploratory phase.
Unfortunately, neoplastic cells are very effective in developing biochemical mechanisms that allow cellular resistance to medicaments or ionising radiation. In fact, resistance is a common clinical problem in the therapy of neoplastic diseases [Cun-Yu Wang, Nature Medicine, 5, 412-417, 1999]. In order to overcome this resistance, therapy generally involves more than one medicament or combinations of ionising radiation and medicaments. Several types of resistance are known, e.g. enhanced drug metabolism, altered drug accumulation, drug target amplification and repair of damaged targets. Resistance to apoptosis is another type of multi-drug resistance, that likely explains a significant proportion of treatment failures [Fisher, Cell, 78, 539-542, 1994]. For convenience, the terms xe2x80x9cmedicamentxe2x80x9d and xe2x80x9cdrugxe2x80x9d are used interchangeably, and are intended to indicate the same.
Clearly, there is a need for new and improved methods in the treatment of neoplastic diseases. Direct manipulation of the factors controlling apoptosis (programmed cell death) is a more recently suggested approach to therapy of neoplastic diseases. Apoptosis is a genetically encoded cell death programme characterised by an xe2x80x9cactive decisionxe2x80x9d by the cell based on information from its environment, its own internal metabolism, its developmental history, etc to die. Unlike cells undergoing necrosis, cells stimulated to enter apoptosis are often capable of survival, but opt to die for the good of the whole organism. Apoptosis is also different from necrosis in that necrosis is often associated with traumatised tissue and cell bursts, whereas the cells condense in the course of apoptosis, and are degraded intracellularly in a controlled manner [Tran, Science and Medicine, 6, 18-27, 1999; Williams, Trends Cell Biol., 2, 263-267, 1992].
At the cellular level it is well recognised that nuclear factor xcexaB (NF-xcexaB) plays a pivotal role in apoptosis. It is also described that an NF-xcexaB inhibitor, IxcexaB, and an IxcexaB kinase complex, IKK, control the level of activated NFxcexaB [Levkau, 1, 227-233, 1999; Wang, Science, 274, 784-787, 196; Madrid, Molecular and Cellular Biology, 5, 1626-1638, 2000]. Accordingly, the NF-xcexaB-IxcexaB-IKK system has been suggested as a target in the treatment of neoplastic diseases.
Cusack, Cancer Research, 60, 2323-2330, 2000 and Wang, Nature Medicine 5, 412-417, 1999 teach that a particular chemotherapeutic, namely the topoisomerase I inhibitor 7-ethyl-10-[4-(1-piperidino)-1-piperidino]-carbonyloxycamptothecin (CPT-11) promotes the activation of NF-xcexaB in cells to induce resistance towards itself, and that a adenoviral transfer of an IxcexaB, IxcexaBxcex1, to inhibit NFxcexaB promotes chemosensitivity to treatment with CPT-11.
WO98/37228 teaches that an agent which decreases IKK activity or that alters the association of IKK and IxcexaB can be useful for allowing apoptosis to occur in a tumour cell by increasing the level of unphosphorylated IxcexaB, which can bind to NF-xcexaB and decrease the level of active NF-xcexaB in the tumour cell.
Rossi, Nature, 403, 103-108, 2000 teaches that cyclopentenone prostaglandins inhibit IxcexaB kinase, and that this makes cyclopentenone prostaglandins potentially valuable in the treatment of cancers, inflammation and viral infections.
It has surprisingly been found that a certain class of cyanoguanidine derivatives is capable of modulating the activity of IxcexaB kinase (abbreviated IKK in the following). By modulating the activity of IKK in the cells it is possible to control the level of activated NF-xcexaB in the cells. Such cyanoguanidines are therefore considered useful in the treatment of neoplastic diseases and other conditions believed to be affected by the level of activated NFxcexaB, e.g. inflammation.
Accordingly, in one aspect the invention relates to a method of modulating the level of activated NF-xcexaB in cells by contacting cells with a compound of general formula I 
wherein
n is 0, 1 or 2;
each R independently represents halogen, trifluoromethyl, hydroxy, C1-4 alkyl, alkoxy or alkoxycarbonyl, nitro, cyano, amino, sulfo or carboxy;
Q is straight or branched, saturated or unsaturated C4-20 divalent hydrocarbon radical;
X is a bond, O, S, amine, carbonyl, carbonylamino, aminocarbonyl, oxycarbonyloxy, oxycarbonyl, carbonyloxy, aminocarbonyloxy, aminothiocarbonyloxy, oxycarbonylamino or oxythiocarbonylamino;
A is di-(C1-4 alkoxy)phosphinoyloxy, C1-4 alkoxycarbonyl, C1-4 alkoxycarbonylamino, a saturated or unsaturated C3-12 carbocyclic ring or C3-12 heterocarbocyclic ring optionally substituted with one or more R1; R1 being independently selected from the group consisting of halogen, trifluoromethyl, hydroxy, C1-4 alkyl, C1-4 alkoxy, C1-4 alkoxycarbonyl, nitro, cyano, amino, carboxy, sulfo, carboxamido, sulfamoyl or C1-4 hydroxyalkyl;
or a pharmaceutically acceptable salt, N-oxide or N-substituted prodrug thereof, in an amount effective to modulate the activity of IKK.
In another aspect, the invention relates to a method of reducing the anti-apoptotic effect of NFxcexaB by contacting the cells with a compound of general formula I, as defined above, in an amount effective to inhibit IKK.
In a further aspect, the invention relates to a method of reducing resistance of cancer cells to chemotherapeutic agents and/or ionising radiation by contacting cancer cells with a compound of the general formula I, as defined above, in an amount effective to down-regulate the activity of IKK.
In a still further aspect, the invention relates to a method of inhibiting the IKK complex by contacting cells with a compound of general formula I, as defined above, in an amount effective to inhibit IKK.
In a still further aspect, the invention relates to a method of screening for cyanoguanidine compounds capable of inhibiting IKK or a subunit thereof, the method comprising contacting IKK or a subunit thereof or a cell expressing IKK or a subunit thereof with a cyanoguanidine compound and identifying the cyanoguanidine compound as being capable of inhibiting IKK or a subunit thereof by determining a change in NF-xcexaB activity in the presence of said cyanoguanine compound compared to the level of NF-xcexaB activity in the absence of said cyanoguanidine compound, or alternatively by determining a change in the phosphorylating activity of IKK in the presence of said cyanoguanine compound compared to the level of phosphorylating activity of IKK in the absence of said cyanoguanidine compound.
In a still further aspect the invention relates to the use of a compound of general formula I, as defined above, for the preparation of a medicament for the prevention or treatment of diseases or disorders associated with increased levels of NF-xcexaB activity in cells and/or associated with upregulated IKK activity in cells and/or to reduce the resistance of cancer cells to chemotherapeutic agents and/or ionising radiation.